This invention relates to an improved orthotic device for use in a new assembly of knee brace or knee stabilizer and modified cast brace. More particularly, this invention relates to a new and improved bi-axial hinged side brace orthotic device with flexion and extension limiter inserts, such as index blocks, for use in support and alignment of the knee joints, security of limb position, prevention of change in position attributed to rotatory forces on the fracture site, prevention of injury or reinjury, prevention of swelling complications, and economy of physician's time. Support and protection is useful for medial or lateral application.
The knee-joint is made up of two condyloid joints and a third joint, partly arthrodial, but not completely so, since the articular surfaces are not mutually adapted to each other, so that the movement is not a simple gliding one. The principle movements that take place at the knee-joint are flexion and extension. The movement of flexion and extension at this joint differ from those in a typical hinge joint, such as the elbow, in that the axis around shich motion takes place is not a fixed one but shifts forward during extension, as a gliding movement is superimposed on the rolling, and shifts backward during flexion.
Although the knee-joint has been described as a hinge joint, it is really of a much more complicated character. It must be regarded as consisting of three articulations, of two different kinds. The first kind is a condyloid articulation; in this form of joint, an ovoid articular surface, or condyle, is received into an elliptical cavity in such a manner as to permit flexion, extension, abduction, adduction, and circumduction, but no axial rotation. The second kind of articution involved is arthrodial; this is a joint which permits only gliding movement. It is formed by the apposition of plane surfaces, or one slightly concave, the other slightly convex, the amount of motion between them being limited by the ligaments of osseous processes surrounding the articulation.
Persons who have sustained knee injuries, who have had operations to remove cartilage, or who have weak knee-joints from various causes, such as arthritis or atheletes who have sustained an injury to the medial collateral ligament or lateral collateral ligament of the knee such as hyper extension and cruciate ligaments, need protection principally against lateral motion of the knee, that is, motion may be the result, for example, of a blow to the side of the knee. At the same time, a suitable knee brace should not interfere with the normal flexion and extension of the leg. The brace should protect the knee against sidewise motions during both flexion and extension, this means that the bracing structure should continue to lie parallel to the parts of the leg above and below the knee-joint in all positions of the brace structure and should remain substantially at the knee and provide protection to the knee.
The knee-joint has four principal ligaments, one on either side and two on the inside. These ligaments may be strained or torn in sports and accidents. Injuries to these ligaments can be serious and must be properly treated if disability is to be avoided. Above all, repeated injury or strains before healing must be avoided. All degrees of ligament injuries will lead to some atrophy of the quadriceps and hamstring muscle groups.
Many previous orthotic devices for use as knee braces and protection devices have been simple hinged structures pivotable about a fixed point, which cannot move parallel to the complex motion of the knee joint. Some knee braces for support and protection of the knee-joint comprises both an inner and outer bracing structure, each a rigid planar and elongated arm and pivoted about a fixed point. The fixed point lies on and parallel to the knee and leg. During motion and a sideways blow, the rigid planar arms may cause further injury or discomfort to the already injured ligaments of the knee-joint.
Some of the previous knee braces fail to provide protection of the injured knee ligaments. While other braces may lie parallel to the leg and knee-joint while it is extended, when the leg is flexed, the bracing structure fails to follow the motion accurately.
The instant orthotic device employs a bi-axial polycentric hinge which is desirable for use with knee-joint movement, and therefore may be used in cast bracing for derotational or knee bracing; also used to distribute the load of functional below-the-knee fracture bracing. Cast bracing stresses proper alignment of the joints, security of limb position, prevention of swelling complications and economy of physician's time. A feature of this invention is the bi-axial hinged orthotic device is a brace-like device that can be utilized in paired configuration on each side of the knee-joint. The special feature of the improved modified cast brace of this invention is a modified bi-axial hinge double axis joint that restricts the arc of the leg motion to safe limits. Functionally, the use of the instant modified cast brace joint compares favorably with previous treatments. Early motion was extremely well tolerated, the stability of operated knees was well supported and aided in management of serious knee ligament injuries.
Clinical and laboratory evidence has proved that prolonged immobilization is detrimental to synovial joints. Traditional treatment of knee-joint and leg injuries commonly involves immobilization for six to eight weeks. Periods of immobilization of this length produce alterations in the biochemistry of connective tissue, the micro- and ultra-structure of synovial membrane, cartilage, tendon, and in the biomechanical properties of the ligament-bone unit. Muscle atrophy and vascular thrombi are common extra-articular complications of prolonged immobilization.
Means for minimizing the undesirable effects and management of fractures are desirable. Therefore, early protected motion will result in minimizing the undesirable effects. The instant invention is a specific modified cast brace which allows adjustable extension and flexion limits as well as locked positions of the knee motion, yet protecting healing structures from disruptive stresses.